1. Field of the Invention
The invention relates to in-line roller skates and more particularly to an improved mechanical lock for linking the hub and the tire of an in-line roller skate as well as loading of the wheel bearings.
2. Description of the Prior Art
In-line roller skating is a popular recreational activity. A growing commercial market for such skates has developed in the United States and elsewhere in response to this trend. The market is directed to providing a faster and more responsive skate that is easily manufactured. The term "in-line skating" is derived from the arrangement of the skate's wheels. In-line skate wheels are arranged longitudinally one behind the other so that the wheels rotate in the same longitudinally oriented vertical plane, similar to ice skating where there is a blade all in one plane. This aligned arrangement of wheels approximates the blade of an ice skate. By arranging the wheels of a roller skate in the same vertical plane, resistance to turning the skate is minimized.
In-line roller skate wheel arrangements often have an elastomeric tire bonded around a wheel hub assembly. The hub and wheel arrangement typically incorporate either dual or single bearing assemblies. In either case, the hub has typically been constructed of hard plastic with a soft elastomeric tire bonded to the radially outer surface thereof. In recognition of the difficulty in maintaining the bond between the tire and hub and of the intricacies of the load carrying requirements, the rims at the outer edges of the hubs have been formed in many different configurations. Examples include configurations where the radially outer surfaces are flat in the axle direction, slightly convex to be formed with a slightly raised central portion or even somewhat V-shaped to form a radially outwardly raised central rib about which the tire is fitted to be bonded thereonto. Often times the tire also includes a shock absorbing element such as a hard ring embedded in the tire or even a soft annular tube embedded in the tire. Such hub and tire arrangements, in practice, must bear various different and varying load vectors which subject the tire to both axial and lateral displacement and, of course, flex the configuration of the tire at the point where the load is carried. When the wheels are in rotational longitudinal movement the portion of the tire in contact with the road surface elastically deforms causing other portions of the elastomeric tire to bulge, most prominently occurring at the portion of the tire ahead of the portion contacting the surface. The bulge tends to squat ahead of the tangent to the vertical diameter physically resisting the rotation of the skate wheel. Such continuous transformational bulging also tends to, over time, cause the elastomeric tire to slip and break from bonded relation and sometimes even roll off the wheel hub, thus subjecting the skater to possible injury.
Prior efforts to provide a hub configured to mechanically lock the tire in place have included a hub assembly with two side plates clamped together to trap roller bearings in a track surrounding the axle and at the outer edge clamping against the opposite sides of an annular tire rib. U.S. Pat. No. 1,618,496 to Ware is an example of this type of arrangement. Wheel hubs of this type are unsatisfactory for present day high-performance wheels requiring smooth bearing performance and a positive lock of the tire in position.
Other efforts to provide a satisfactory hub and wheel arrangement have lead to proposing a hub and bearing assembly about an axle tube and circumscribed by annular rings intended to clamp at their radially outer extremities against the opposite sides of a tire configured with laterally disposed tire seats. A device of this type is shown in U.S. Pat. No. 1,697,485 to Ware. Such an arrangement fails to provide for a relatively rigid force line to the hub and positive locking of the tire against movement relative to the hub. Thus, there exists a need for a skate wheel assembly wherein the hub is positively linked to the wheel to securely lock the wheel in position and prevent rotation of the tire relative to the hub.
In-line roller skate wheels generally incorporate either dual or single bearing assemblies centered axially in the wheel hubs in series along a straight longitudinal center line under the skate shoe. The mechanical relationship of the outer and inner races around the bearings often lacks precision due to cost-determined manufacturing tolerances. This lack of precision causes wandering and play between the outer bearing race and the inner bearing race, and thus wandering and play between the elastomeric tire and the axle as the wheels rotate about their axes. This shortcoming causes uneven wear to the bearings, the wheel hubs, and the elastomeric tires. Additionally, the cost driven lack of precision in some bearing assemblies provides unstable support for the user's weight during the recreational activity and diminished balance and support for boot and skater.
It has been proposed to provide roller skates having wheels disposed in staggered relationship on the opposite sides of a central mounting beam. A device of this type is shown in U.S. Pat. No. 5,251,920 to McHale. However, such an arrangement in addition to not providing the performance characteristic of wheels which are of the classic in-line configuration, fails to address the issue of off-center loading of the individual bearing assemblies.